Foam dispensing pump container

Abstract

A foam dispensing pump container, for dispensing foam by mixing air pumped from an air cylinder by an air piston having suction holes in its upper wall and a foamable liquid pumped from a liquid cylinder by a liquid piston having an annular projection on its outer wall, provided with an elastic valve member including a cylindrical wall portion, an outer thin annular valve portion extending outwardly from the cylindrical wall portion, and an inner thin annular valve portion extending inwardly from the cylindrical wall portion. The elastic valve member is arranged such that the cylindrical wall portion is in contact at least partially with an inner surface of the upper wall between the suction holes and an air passage, the outer thin annular valve portion is in contact, at its outer annular rim portion, with an inner surface of the upper wall extending outwardly beyond the suction holes, and the inner thin annular valve portion is in contact, at its inner annular rim portion, with the annular projection of the liquid piston below the air passage.

What is claimed is: 
     
       1. A foam dispensing pump container comprising: a lid means; a double cylinder which is fastened to the container by the lid means mounted on an opening portion of said container and which comprises an air cylinder and a liquid cylinder which is smaller in diameter than said air cylinder, both arranged concentrically; an air piston accommodated in said air cylinder for reciprocal movements in an axial direction of said air cylinder and urged upwardly by a spring means, an air chamber formed below said air piston in said air cylinder; a liquid piston accommodated in said liquid cylinder for reciprocal movements in an axial direction of said liquid cylinder and urged upwardly by said spring means, said liquid piston forming, in conjunction with said air piston, an integral piston body having a hollow rod portion extending upwardly through an opening of said lid means; a liquid chamber formed below said liquid piston in said liquid cylinder; an air passage formed in a space defined by inner surfaces of an upper portion of said air piston and outer surfaces of said liquid piston; a liquid passage formed in said liquid piston, a mixing chamber formed above and communicating with both said air chamber and said liquid chamber through said air passage and said liquid passage respectively; a hollow bent nozzle member having a nose portion and a stem portion and mounted at its stem portion to an upper end of said piston body; a foam passage formed through said nozzle member and communicating with said mixing chamber; at least one porous member disposed across said foam passage; a first check valve disposed in a lower end portion of said liquid chamber and adapted to be opened when a negative pressure is created in said liquid chamber; a dip tube attached to a lower end of said liquid cylinder below said first check valve and extending to a bottom portion of said container; a second check valve at least partially disposed in an upper end of said liquid passage for opening an outlet of said liquid passage to said mixing chamber when said liquid chamber is pressurized; an air hole disposed in said air cylinder for introducing external air into a head space created in said container when said container is filled to a fill level; at least one suction hole provided in an upper wall of said air piston; and a third check valve disposed to be adapted to open and close said at least one suction hole for introducing air into said air chamber when a negative pressure is created in said air chamber, wherein said third check valve includes an elastic valve member, comprising a cylindrical wall portion, an outer thin annular valve portion extending outwardly from said cylindrical wall portion and an inner thin annular valve portion extending inwardly from said cylindrical wall portion, and being held at an inner surface of said upper wall of said air piston,   said cylindrical wall portion at least partially contacting a first portion of said inner surface of said upper wall extending between said suction hole and said air passage, said outer thin annular valve portion contacting, at an outer annular rim portion, a second portion of said inner surface of said upper wall extending outwardly beyond said suction hole, and said inner thin annular valve portion contacting, at an inner annular rim portion, an annular projection which is formed below said air passage and on an outer surface of said liquid piston.   
     
     
       2. A foam dispensing pump container according to claim 1, wherein the first portion of the inner surface of the upper wall of said air piston which comes in contact with the cylindrical wall portion of said elastic valve member is vertically disposed.   
     
     
       3. A foam dispensing pump container according to claim 1, wherein the outer thin annular valve portion of said elastic valve member has a generally concaved upper surface and a generally convexed lower surface, and the inner thin annular valve portion of said elastic valve member has a generally convexed upper surface and a generally concaved lower surface.   
     
     
       4. A foam dispensing pump container according to claim 2, wherein the outer thin annular valve portion of said elastic valve member has a generally concaved upper surface and a generally convexed lower surface, and the inner thin annular valve portion of said elastic valve member has a generally convexed upper surface and a generally concaved lower surface.   
     
     
       5. A foam dispensing pump container according to claim 1, wherein the piston body moves vertically and the second check valve comprises: a rod valve member disposed in said liquid passage and adapted to be forcibly moved up and down by a given amount in accordance with the vertical movements of said piston body; and   a cylindrical retaining member having an upper cylindrical portion fitted snugly in said liquid passage and disposed in said liquid chamber for engaging at its inner surfaces with, and restricting vertical movements of said rod valve member such that the outlet of said liquid passage to said mixing chamber is closed by an upper portion of said rod valve member while said piston body is moving up and said rod valve member is held engaged at a lower portion with said cylindrical retaining portion and prevented from moving upwards while said outlet of said liquid passage remains closed when said piston body is at a top dead position of its reciprocal movement, but said liquid passage and the outlet of said liquid passage to said mixing chamber are opened as said piston body moves down, and when said piston body is at a bottom dead position of its reciprocal movements and said nozzle member is in engagement with said lid means, said liquid passage is closed by said rod valve member and said rod valve member is snugly fitted in the upper cylindrical portion of said cylindrical retaining member which is snugly fitted into a portion of said liquid piston forming said liquid passage, and prevented from moving down.   
     
     
       6. A foam dispensing pump container according to claim 2, wherein the piston body moves vertically and the second check valve comprises: a rod valve member disposed in said liquid passage and adapted to be forcibly moved up and down by a given amount in accordance with the vertical movements of said piston body; and   a cylindrical retaining member having an upper cylindrical portion fitted snugly in said liquid passage and disposed in said liquid chamber for engaging at its inner surfaces with, and restricting vertical movements of said rod valve member such that the outlet of said liquid passage to said mixing chamber is closed by an upper portion of said rod valve member while said piston body is moving up and said rod valve member is held engaged at a lower portion with said cylindrical retaining portion and prevented from moving upwards while said outlet of said liquid passage remains closed when said piston body is at a top dead position of its reciprocal movement, but said liquid passage and the outlet of said liquid passage to said mixing chamber are opened as said piston body moves down, and when said piston body is at a bottom dead position of its reciprocal movements and said nozzle member is in engagement with said lid means, said liquid passage is closed by said rod valve member and said rod valve member is snugly fitted in the upper cylindrical portion of said cylindrical retaining member which is snugly fitted into a portion of said liquid piston forming said liquid passage, and prevented from moving down.   
     
     
       7. A foam dispensing pump container according to claim 3, wherein the piston body moves vertically and the second check valve comprises: a rod valve member disposed in said liquid passage and adapted to be forcibly moved up and down by a given amount in accordance with the vertical movements of said piston body; and   a cylindrical retaining member having an upper cylindrical portion fitted snugly in said liquid passage and disposed in said liquid chamber for engaging at its inner surfaces with, and restricting vertical movements of said rod valve member such that the outlet of said liquid passage to said mixing chamber is closed by an upper portion of said rod valve member while said piston body is moving up and said rod valve member is held engaged at a lower portion with said cylindrical retaining portion and prevented from moving upwards while said outlet of said liquid passage remains closed when said piston body is at a top dead position of its reciprocal movement, but said liquid passage and the outlet of said liquid passage to said mixing chamber are opened as said piston body moves down, and when said piston body is at a bottom dead position of its reciprocal movements and said nozzle member is in engagement with said lid means, said liquid passage is closed by said rod valve member and said rod valve member is snugly fitted in the upper cylindrical portion of said cylindrical retaining member which is snugly fitted into a portion of said liquid piston forming said liquid passage, and prevented from moving down.   
     
     
       8. A foam dispensing pump container according to claim 1, further comprising: a sliding seal portion formed on an outer circumferential portion of said air piston and adapted to move up and down in close sealing contact with inner wall surfaces of said air cylinder in accordance with the reciprocal movements of said piston body, said sliding seal portion being sized and shaped to close said air hole formed in said air cylinder, when said piston body is at a top dead position of its reciprocal movements.   
     
     
       9. A foam dispensing pump container according to claim 2, further comprising: a sliding seal portion formed on an outer circumferential portion of said air piston and adapted to move up and down in close sealing contact with inner wall surfaces of said air cylinder in accordance with the reciprocal movements of said piston body, said sliding seal portion being sized and shaped to close said air hole formed in said air cylinder, when said piston body is at a top dead position of its reciprocal movements.   
     
     
       10. A foam dispensing pump container according to claim 3, further comprising: a sliding seal portion formed on an outer circumferential portion of said air piston and adapted to move up and down in close sealing contact with inner wall surfaces of said air cylinder in accordance with the reciprocal movements of said piston body, said sliding seal portion being sized and shaped to close said air hole formed in said air cylinder, when said piston body is at a top dead position of its reciprocal movements.   
     
     
       11. A foam dispensing pump container according to claim 4, further comprising: a sliding seal portion formed on an outer circumferential portion of said air piston and adapted to move up and down in close sealing contact with inner wall surfaces of said air cylinder in accordance with the reciprocal movements of said piston body, said sliding seal portion being sized and shaped to close said air hole formed in said air cylinder, when said piston body is at a top dead position of its reciprocal movements.   
     
     
       12. A foam dispensing pump container according to claim 8, further comprising: an annular seal portion formed on a portion of said outer circumferential portion of said air piston above and at a predetermined distance from, said sliding seal portion and sized and shaped to close said air hole of said air cylinder; and   an air passage forming portion disposed in an upper wall portion of said air cylinder for forming an air passage between itself and said annular seal portion on said air piston for allowing air to pass therethrough when said piston body is within a predetermined range between the top dead position and a bottom dead position,   both arranged such that said sliding seal portion of said air piston closes said air hole when said piston body is at its top dead position and said annular seal portion of said air piston closes said air hole when said piston body is at its bottom dead position and said nozzle member is in engagement with said lid means.   
     
     
       13. A foam dispensing pump container according to claim 9, further comprising: an annular seal portion formed on a portion of said outer circumferential portion of said air piston above and at a predetermined distance from, said sliding seal portion and sized and shaped to close said air hole of said air cylinder; and   an air passage forming portion disposed in an upper wall portion of said air cylinder for forming an air passage between itself and said annular seal portion on said air piston for allowing air to pass therethrough when said piston body is within a predetermined range between the top dead position and a bottom dead position,   both arranged such that said sliding seal portion of said air piston closes said air hole when said piston body is at its top dead position and said annular seal portion of said air piston closes said air hole when said piston body is at its bottom dead position and said nozzle member is in engagement with said lid means.   
     
     
       14. A foam dispensing pump container according to claim 10, further comprising: an annular seal portion formed on a portion of said outer circumferential portion of said air piston above and at a predetermined distance from, said sliding seal portion and sized and shaped to close said air hole of said air cylinder; and   an air passage forming portion disposed in an upper wall portion of said air cylinder for forming an air passage between itself and said annular seal portion on said air piston for allowing air to pass therethrough when said piston body is within a predetermined range between the top dead position and a bottom dead position,   both arranged such that said sliding seal portion of said air piston closes said air hole when said piston body is at its top dead position and said annular seal portion of said air piston closes said air hole when said piston body is at its bottom dead position and said nozzle member is in engagement with said lid means.   
     
     
       15. A foam dispensing pump container according to claim 11, further comprising: an annular seal portion formed on a portion of said outer circumferential portion of said air piston above and at a predetermined distance from, said sliding seal portion and sized and shaped to close said air hole of said air cylinder; and   an air passage forming portion disposed in an upper wall portion of said air cylinder for forming an air passage between itself and said annular seal portion on said air piston for allowing air to pass therethrough when said piston body is within a predetermined range between the top dead position and a bottom dead position,   both arranged such that said sliding seal portion of said air piston closes said air hole when said piston body is at its top dead position and said annular seal portion of said air piston closes said air hole when said piston body is at its bottom dead position and said nozzle member is in engagement with said lid means.